Add showing and modifying user name (#306)

Make sure to use the user name field everywhere

Add showing and modifying user name

Co-authored-by: kolaente <k@knt.li>
Reviewed-on: https://kolaente.dev/vikunja/frontend/pulls/306
Co-Authored-By: konrad <konrad@kola-entertainments.de>
Co-Committed-By: konrad <konrad@kola-entertainments.de>

src/services/userName.js

@@ -0,0 +1,10 @@
+
+import AbstractService from './abstractService'
+
+export default class UserNameService extends AbstractService {
+	constructor() {
+		super({
+			update: '/user/settings/name',
+		})
+	}
+}